Conventional types of liquid crystal display apparatus have a transmissive liquid crystal panel and a backlight behind such a liquid crystal panel.
To a human eye, even if the middle section is bright and peripheral sections are somewhat dark, a screen appears to have a uniform surface light source. Thus, in order to enhance brightness at the middle section of a screen, an LED distribution density is adjusted by arranging an LED substrate closer to the middle section of the screen. Further, the number of LEDs mounted can be reduced by employing a configuration where the shape of a reflective sheet is tilted at peripheral sections of a screen. FIG. 8 illustrates a configuration that reduces the number of LEDs mounted and enhances the brightness at the middle section of the screen in this manner.
FIG. 8 is a plan view that schematically illustrates an example of an LED module arrangement in a conventional LED light source apparatus.
In FIG. 8, a conventional LED light source apparatus 100 is constituted of a plurality of LED modules 101. Here, rectangular LED modules 101 are arranged in a traverse direction in four rows for convenience. Among the four rows of rectangular LED modules 101 in the traverse direction, the rectangular LED modules 101 in the middle two rows are arranged closer to each other toward the middle to enhance brightness at the middle section of the screen.
Each LED module 101 has a printed circuit board 102 and a plurality (10 in this case) of LEDs 103 mounted thereon in series.
A reflective sheet 104 has a plurality of holes for the LEDs 103 to penetrate. The printed circuit board 102 and the reflective sheet 104 are secured in a state where the LEDs 103 penetrate the penetration holes for LEDs from the backside. Lights from a plurality of LEDs 103 are reflected and irradiated forward by the reflection sheet 104 to be a surface light source. The four oblong longitudinal and traverse surfaces of the peripheral section of the screen (peripheral frame section of the screen) of the reflection sheet 104 are constituted by tilted surfaces to open forward.
In this manner, Patent Literature 1 discloses an example in which a plurality of LED modules in the middle rows are placed closer to each other toward the middle to arrange LEDs at a higher density in comparison to the peripheral sections in order to enhance brightness at the middle section of the screen.